Resetting gauge for internal screw thread cutters



Jan. 15, 1946. c, H. SAPPER RESETTING GAUGE FOR INTERNAL SCREW TH READ CUTTER Filed Jan. 18, 1944 R; mm m H 2 s k W M Y Patented Jan. 15, 1946 UNITE-D stares orrrce RESETTINGGAUGE FOR'INTERNALSSCREW "THREAD commits Gharles Sapper, Broolilyn, N. Am lication'lanuary 18, 1944,5Serial No..518,'689

l-Claims. (Cl. 33185) This .invention relates ito. a-device .for resetting a cutting tool for recutting "internal screw threads.

In recutting ram-internal thread because it is mashed, imperfect, worn, or for any reason, it is necessary to reset the cutter in the lathe or thread cutting machine. This makes it necessary to back the cutter away from the work by releasing the carriage from the feed screw and to release the cutter from the tool post on the carriage and then reset the cutter. cutter under these conditions is diificult and without assurance that the cutter is reset with accuracy or in proper registry for the thread recutting operation.

The principal object of the present invention is the provision of a device of the character mentioned which will enable the resetting of a thread cutting too] quickly, easily and accurately to the end that a thread may be properly recut to the desired or required size and pitch.

The nature of the invention and its distinguishing features and advantages will appear when the following specification is read in conjunction with the accompanying drawing, in which:

Fig. 1 is a top plan view of the device of the present invention in use and the work in which an internal thread is to be recut is shown partly in section.

Fig. 2 is a transverse sectional view taken on the line 2-2 of Fig. 1.

Fig. 3 is a perspective view of the gauge clamp per se.

Fig. 4 is a sectional view taken on the line 44 of Fig. 3.

Referring now more particularly to the drawing, it will be apparent the device generally stated consists of a gauge member or template l and a clamp II for holding the gauge member 10 in place with respect to a piece 'of work 12 to enable the resetting of a thread cutting tool 13.

The gauge member 10 consists of an elongated flat piece of metal having teeth I4 formed on one longitudinal edge. The teeth [4 correspond to the conventional standard V thread. Teeth I5 are formed on the other longitudinal edge of the member I0 and these teeth have slightly straight or rounded tops and bottoms and in other respects correspond to the teeth 14. The teeth l5 so formed are adapted to seat more perfectly in contact with inaccurate or deformed threads.

The clamp H includes cooperative clamping parts or members l6 and I1 respectively, the part I1 being slidably related to the part It by means The resetting of the .of :;a .slide l8 -slida-ble ronrthe part H5.- .The part 16 isof angular/formation or i L. shape .to provide portions l9 and 20 -:r.espectively. The portion 4.9 is .U shape in .cross-rsection :and merges into -.the

portions 20. The portions 20 are spaced to ac commodate the gauge member ID therebetween. A pin 2i is supported by the portions 20 between the same and serves to engage between two of the teeth M. The slide I8 is slotted to receive the portion IQ of the part 16 and carries pins 22 offset with respect to each other and engageable with the opposite longitudinal sides respectively of said portion I9 to cause the slide to ride smoothly along the portion ill to different positions of adjustment with respect to the part IS. The pins 22 also prevent the slide 3 from becoming cocked when the screw 23 is manipulated to set up the clamping action. The clamping part I! has a screw 23 swivelly connected therewith as at 24. The screw 23 is in threaded engagement with the slide l8. One end 25 of the part I! is reduced and projects into the groove provided by the portion IS in order to prevent the part i I! from turning. The part I! is of U shape in cross-section to afford a good grip on the work, especially when it has a cylindrical surface as shown in the present instance with respect to the work l2.

The gauge member or template II] in association with the clamp l l extends between the portions 20 of the part IS. The gauge member may be adjusted or set in any satisfactory relation to the part IE to project partly interiorly of the tapped bore in the work and partly exteriorly thereof, as shown in Fig. 1. The gauge member I0 is placed in accurate registry in which the teeth l5 are brought into meshing contact with the threads of the work. The pin 2| is engaged between two teeth I in contact therewith to impose pressure on the gauge member In when it is clamped. The clamping action is effected by moving the slide l8 along the portion H! to bring the clamping part I! into contact with the work I2. The screw 23 is then manipulated to set up a clamping action of the part I! in conjunction with the pin 2|. The gauge member ID is thus securely held in the tool resetting position. The cutter l3 which has been drawn clear of the Work is made loose in the tool post. The carriage on which the tool post is mounted is adjusted to bring the point of the cutter between two of the teeth M on the exteriorly projecting portion of the gauge member 10 in proper registry. The cutter I3 is then secured on the tool post in the registered position resetting the g 7 1: ff: f

It will be obvious there is described a device which aids a machinist in cutting threads with a machine tool, because it is possible to resetthe cutter accurately to recut the thread if the thread is faulty due to the hardnesszor toughness,

of the material, and in case; a cutter breaks .or becomes dull or wears off before the thread has been finished.

Iclaim: V 1 A device for resetting a screw thread cutter comprising a gauge member consisting of an elongated flat piece of metal having teeth on each-of its longitudinal edges to correspond to standard screw threads, the teeth on one edge to accurately contact screw threads to be recut and the teeth on the other edge to enable the cutter to be reset by engaging some of the teeth last mentioned for the thread recutting operation, and means to secure said gauge member in the resetting position.

2. A device as set forth in claim 1, wherein said means consists of a clamp. i

3. A device as set forth in claim 1; wherein said means includes cooperative clamping parts,

' and the gauge member is adjustably engaged with one of said parts. 4; A device for resetting a screw thread cutter comprising a gauge member having teeth formed to accuratelycontact screw threads to be recut and when so placed to enable the cutter to be reset in'contact therewith for the thread recutting operation, and means to secure said gauge member in the resetting position, said means including a clamping part having a portion to en gage the gauge member.

CHARLES H. SAPPER. 

